Google announced the launch of a new AdSense ad type that shows when they are likely to perform well and provide a good user experience.
The new page-level ads are designed for mobile pages and come in two formats - anchor/overlay and vignette formats. Google indicated that additional formats are on their way.
A one-time set up is required to place the code for page-level ads where the ads should be shown. Publishers will be able to adjust the setting in their account and enable new ad formats without having to make any modifications to that code.
Google has published some useful information on Page-level ads in its Help Center addressing benefits, integration and testing.